Battle of Messines

The Battle of Messines was fought from 7 to 14 June 1917 on the Western Front of World War I when the British launched an offensive against the Imperial German Army amid the Nivelle Offensive. The British detonated 19 mines beneath the German front position, and the shockwave from the explosion was heard as far away as London and Dublin; it was the largest planned explosion in history until 1945, killing 10,000 German soldiers instantly.

Background
The First and Second Battles of Ypres in 1914 and 1915 left the British holding a salient, facing German troops entrenched on higher ground. From early 1916, British commander-in-chief Field Marshal Douglas Haig favored an offensive at the Ypres salient, but the need to cooperate with the French led to operations at the Somme and Arras. The failure of the French Nivelle Offensive in spring 1917 and subsequent mutinies in the French army left the British to pursue their own plans. Haig envisaged a major offensive at Ypres, in preparation for which the British 2nd Army would seize Messines Ridge.

Battle
In early May 1917, British Second Army commander General Herbert Plumer, commander in the Ypres salient since 1915, was ordered to prepare an operation to take the low German-held ridge stretching from Messines to Wystchaete and a position known as Hill 60, 3 miles southeast of Ypres. This would strengthen the British position south of Ypres as the prelude to a larger Flanders offensive farther north. Plumer had proposed an attack on Messines as early as January 1916.

The underground war
By 1917, preparations were well advanced for destroying the German defenses with buried explosives. The waterlogged ground in Flanders was on the whole unsuitable for tunneling, but at Messines British Royal Engineers had found a usable layer of blue clay at a depth of 80-100 feet. Through 1916, around 30,000 British, Australian, Canadian, and New Zealand soldiers - a combination of military engineers and infantrymen who were miners in civilian life - had dug tunnels forward from their lines and under the German-held ridge. At the end of each tunnel they hollowed out a chamber to hold explosives.

The work of tunneling was arduous, despite the availability of portable oxygen tanks, electric light, and eventually mechanical diggers. The task was made more difficult by German countermeasures to locate and blow up the British tunnels. The British also listened for the Germans and mounted counterattacks, digging tunnels at lesser depth to intercept the German tunnelers. Occasionally, miners would break into an enemy tunnel, and hand-to-hand combat ensued. In August 1916, the Germans tunnelers had a major success in this underground war, when they broke into a British chamber and destroyed it.

More than 20 British tunnels remained undetected. The chambers were packed with explosives, much of it sealed in metal containers to protect against the wet conditions. Because tunneling activity subsided toward the end of 1916, the Germans on Messines Ridge became complacent. By spring 1917, they had stopped worrying about mines.

Supply lines
General Plumer was a methodical commander with a reputation for being careful with his soldiers' lives. He had new light railroads constructed behind the British lines to bring up ammunition and other supplies. Because thirst was constant problem for troops in battle, pipelines were laid to ensure a supply of water at the front. An impressive concentration of artillery was assembled along a 10-mile front, with 2,200 guns to support an infantry assault.

Defenses organized in depth
The German defenses presented a formidable challenge. By 1917, the German army had greatly refined its defensive tactics. Instead of facing a line of trenches, Allied soldiers were met with defenses organized in depth. At Messines, this meant four systems of trenches, machine gun emplacements, and concrete pillboxes, backed by further positions. The Germans accepted that an attack would break into these defenses, but counterattack forces held at the rear were to come forward once the enemy onslaught lost momentum and drive the attackers back with heavy losses.

Messines Ridge was held by a corps of the German 4th Army commanded by General Maximilian von Laffert. He chose to maintain unusually large numbers of troops in his front two lines, a decision the Germans came to regret. On 21 May, the British guns began a devastatingly effective preliminary bombardment that lasted for 17 days. Precisely targeted with the assistance of reconnaissance aircraft, British firepower destroyed a large part of the German artillery. German infantry positions were laid to waste. Frontline troops could not be relieved or supplied and ran short of food and water.

Walls of fire
The British attack was launched on 7 June. At 3:10 AM, just before dawn, the mines in 19 of the chambers under Messines Ridge were exploded by the engineers. The mines ranged from 17,000 lb to over 95,000 lb of explosives. Eyewitnesses described sheets of flame, clouds of smoke, and the ground shaking like an earthquake. The sound of the explosions was heard in London, over 100 miles away.

As many as 10,000 German soldiers may have been killed in the eruption. Dazed survivors wandered toward the British lines to surrender. British troops advanced almost unopposed to occupy the German forward positions and prepared to assault the second line. At 7:00 AM, after a considerably delay, the second stage of the assault opened. Troops advanced close behind a creeping artillery barrage, with massed machine guns providing supporting fire over their heads. The soldiers engaged in the assault were chiefly Australians and New Zealanders of the ANZAC Corps, who captured Messines village, and Irish soldiers of the 16th Irish and 36th Ulster divisions. Formed in 1914 around the Catholic Irish Volunteers and the Protestant Ulster Volunteer Force respectively, militias that had been close to fighting one another in a civil war, the Irish forces advanced side by side, taking the village of Wystchaete.

Reserves were fed forward in the afternoon to capture further objectives and consolidate the gains. German counterattacks were slow to materialize and were mishandled, with British artillery fire making it hard for the German troops to get forward. Plumer's plan had been to seize and hold objectives, rather than achieve a total breakthrough. Fighting continued until 14 June, by which time the British were in possession of the ground they had sought to gain, dominating the Gheluvelt plateau. The Germans had lost an estimated 25,000 men, including 7,000 taken prisoner, compared with British losses of 17,000 - a rare instance of the attritional balance favoring the side of the offensive.

Aftermath
The success of the Battle of Messines boosted British morale and encouraged Field Marshal Haig's plans for a full-scale offensive in Flanders. Haig launched the Third Battle of Ypres, known as the Battle of Passchendaele, on 31 July. Continuing through to November, this turned into a vast attritional struggle without decisive result. At least two of the buried mines at Messines remained unexploded after the end of the war. One of them erupted in 1955, fortunately killing only a cow. Since 1998, Messines has been the site of the Irish Peace Tower, commemorating Catholic and Protestant Irish soldiers who died in World War I.